Anthropic Debuts Claude Sonnet 5 As Agentic AI Push Goes Mainstream

Anthropic has introduced Claude Sonnet 5, a more capable option for developers building autonomous "agent" systems that can plan multi-step workflows, use tools, and execute tasks with limited human input.

Sonnet 5 is designed to operate more independently than prior Sonnet versions, including the ability to interact with tools such as web browsers and terminals to complete longer, more complex task chains, the company said in a blog post.

The model is rolling out across its product suite, where it will serve as the default for Free and Pro users.

It will also be available to Max, Team and Enterprise customers, as well as through Claude Code and the Claude Platform API under the name claude-sonnet-5.

Read Also: California Expands AI Push With Statewide Anthropic Partnership On safety, Anthropic said internal testing indicated Sonnet 5 produces fewer undesirable behaviors than Sonnet 4.6 and shows improved resistance to prompt injection attacks and malicious instructions.

The company also emphasized that Sonnet 5 was not explicitly trained for cybersecurity applications and performs significantly below its top-tier Opus models on evaluations involving potentially harmful cyber capabilities. "We did not deliberately train Sonnet 5 on cybersecurity tasks.

It can perform some routine, non-harmful cyber tasks, but on evaluations testing potentially dangerous cyber skills, such as developing software exploits, it shows substantially poorer performance than models such as Opus 4.8 and Mythos 5," the company said.

Anthropic said it has enabled cyber safeguards by default in Sonnet 5, using real-time detection and blocking systems similar to those deployed in its Opus models, while noting the guardrails are less restrictive than those applied to Fable 5.

The company also raised rate limits across Chat, Cowork, Claude Code and the Claude Platform, citing higher token usage associated with increased "effort" settings in the new model.

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